Water 4.0


Water 4.0: The Past, Present, and Future of the World’s Most Vital Resource

by David Sedlak

David Sedlak is a professor of environmental engineering at the University of California, Berkeley. In this book he explains the history, science, engineering, and political aspects of water and sewer systems. First, it may be helpful to decode the title:

  • Water 1.0—a system of importing and distributing water.
  • Water 2.0—drinking water treatment including filtration and chlorination.
  • Water 3.0—sewage treatment.
  • Water 4.0—next-generation water systems.

I will focus on some of the more contemporary topics in this summary.

“Centralized urban water systems are presently under considerable stress from a variety of forces. Increases in population density, changing precipitation patterns, competition for water resources, and recognition of the need to leave more water in streams to protect aquatic habitats are driving a movement toward formerly unusable water sources, such as seawater and wastewater effluent.”

There is an impressive case study of the water reuse system in St. Petersburg, Florida. The city “built a massive nonpotable water reuse system starting in 1977… In the first phase of the project, water from the reuse system was sent to golf courses, parks, and schools. After a few years, the city created a dual distribution network for irrigation of residential properties… The incentive for joining was cost: water from the reuse system was substantially cheaper to a homeowner than potable water …. By 2009, St. Petersburg’s system had expanded to the point where it provided… an amount equivalent to 40 percent of the city’s average daily water use.” Wow!

Redwood City, California proposed a similar system and was met with a public revolt. Key differences were that the Redwood City system was to be mandatory and did not offer a discounted price for the nonpotable water.

There is a chapter on “toilet-to-tap” water recycling systems. Interestingly, the successful operation in Orange County, California evolved from a 1950s effort to prevent seawater from contaminating the water table. Attempts at recycling wastewater into drinking water in San Diego and Los Angeles counties were met with insurmountable public opposition.

Is desalination the silver bullet for coastal cities in arid climates? Beginning in the late 1990s, Israel started planning a network of six desalination plants connected to a distribution canal called the National Water Carrier. Each of the plants was identical, which gave the project economy of scale. Several desalination plants were built in Australia in the 2000s in response to a severe drought. “Because of environmental concerns—including greenhouse gases and protection of coastal ecosystems—as well as the need for each of the country’s desalination plants to be designed, permitted, and built separately, Australia’s desalinated water costs about twice as much as Israel’s.” Tampa, Florida experienced a bumpy ride on the construction of its desalination plant including multiple bankruptcies. “Tampa’s desalinated seawater [also] costs almost twice as much as Israel’s.” A desalination plant in Carlsbad, California is expected to be completed by 2016. As with the Australian plants, there was opposition from environmental groups, resulting in delays and modifications. “The total price for California’s first big coastal desalination plant is estimated to be around $800 million for a plant that will deliver about… 50 million gallons of water each day. On the basis of the dollars per gallon of water delivered, that’s more than twice as high as the costs for water provided by the desalination plants in Tampa and Perth” or four times the cost of Israel’s.

The author notes that emerging technologies “such as forward osmosis, or the development of new types of membranes made from exotic materials like carbon nanotubes, hold promise for reducing the cost of the process.”

Sedlak highlights an urban runoff system in Santa Monica, California. The city “invested $12 million to capture and reuse urban runoff that was contaminating its beloved beaches with waterborne pathogens. The Santa Monica Urban Runoff Recycling Facility (SMURRF) uses microfiltration membranes and ultraviolet disinfection to treat dry weather runoff. Dry weather runoff… is a lot more polluted than the water that flows into the sewers on rainy days. After treatment, the facility provides… water for landscaping irrigation and toilet flushing in the neighborhood along the beach.”

The author suggests that “perhaps the best long-term solution to our water problems will be to abandon centralized water systems altogether… if we can figure out ways to meet our water needs with local resources, to safely treat our wastes close to where they are produced, and to drain the streets without a centralized storm water system, we might break free of the cycle of costly investments and environmental damage that currently plague our current water and wastewater systems… Decentralized water reuse can be achieved by building a network of tiny wastewater treatment plants in the basements of homes and apartment buildings… The key to these autonomous, household wastewater treatment plants is the membrane bioreactor, a technology that employs materials similar to those found in reverse-osmosis membranes—only with larger pores—to separate microbes from treated wastewater.” The author does concede that centralized water systems can accommodate the high volume of water needed for fighting fires.

Sedlak envisions, “in the distributed version of Water 4.0, a shift in public attitudes will make it possible to reduce consumptive water use by around 75 percent through the installation of ultraefficient appliances and elimination of wasteful forms of outdoor water use. In the distributed water future, landscape irrigation with drinking water will be unthinkable… In areas where conditions are right, housing developments will operate without help from the expensive and difficult-to-maintain centralized water infrastructure.”

I recommend this book because it can facilitate a more productive conversation among citizens and policy makers. “Once we better understand the costs and benefits of different approaches, we can make informed choices about supporting or opposing investments in desalination plants, potable reuse systems, graywater recycling systems, and other new forms of infrastructure.”


Sedlak, David. Water 4.0: The Past, Present, and Future of the World’s Most Vital Resource. New Haven: Yale University Press, 2014. Buy from Amazon.com


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